1. Field of the Invention
The present invention generally relates to an apparatus for testing in down hole oilfield applications, and, more particularly to an apparatus for attaching to a sub or "bottom hole" tool so that the application of contaminated fluid such as water under pressure directly to the bottom tool can be forsaken.
2. General Background
In offshore oil and gas drilling the present state of the art requires a "bottom hole" tool or "bottom" tool be placed in a bore hole such that it can expand and contract based upon fluid pressure (usually water) being applied to an inlet port at the top thereof. The apparatus of the present invention is provided for threadable attachment to such "bottom hole" tool so that the application of the fluid pressure directly to the "bottom hole" tool can be obviated.
Several attempts have been made in the prior art to develop testing tools that are designed to test a tubing as the tubing string is being made up and positioned in a well bore.
The following U.S. patents show testing devices that are lowered down a pipe in a well on a string to apply pressure to test the pipe or casing:
U.S. Pat. No. 4,474,055 PA1 U.S. Pat. No. 3,108,467 PA1 U.S. Pat. No. 4,083,230 PA1 U.S. Pat. No. 3,071,960 PA1 U.S. Pat. No. 3,800,596 PA1 U.S. Pat. No. 3,899,920 PA1 U.S. Pat. No. 4,081,990 PA1 U.S. Pat. No. 3,396,575